The present invention generally relates to an excluding unit and more particularly, to an apparatus for removing compressed snow or sheets of ice (referred to as compressed snow hereinafter) from a road.
Conventionally, various arrangements have been proposed as apparatuses for removing compressed snow or the like as referred to above. There has been disclosed, for example, in Japanese Utility Model Laid-Open Publication Jikkaisho No. 62-114920, a removing apparatus which includes a plurality of line cutting teeth provided on the undersurface of a chassis of a vehicle in a direction parallel to the advancing direction thereof, and a blade disposed behind said line cutting teeth, whereby cut lines or grooves are formed in the compressed snow or the like by the line cutting teeth for facilitating the separation of the compressed snow from the road and thereafter, the compressed snow thus treated is separated by the blade and is forced towards the side of the road.
In the known arrangement as described above, however, there has been a problem in that, since underfaces of the line cutting teeth reach and contact the surface of the paved road, the pavement and the line cutting teeth are both undesirably damaged.
In order to solve the problem referred to above, lines or grooves can be formed in the compressed snow and the like with the line cutting means being kept out of contact with the surface of the paved road; other actual methods which may be considered are as follows.
(i) Forming lines or grooves by blowing heated air against the compressed snow, etc. PA1 (ii) Forming lines or grooves by spraying steam onto the compressed snow or the like. PA1 (iii) Forming lines or grooves by bringing blades having heating medium circulating therethrough, into pressure contact with the compressed snow or the like.
In connection with the above, the present inventors carried out experiments for thawing ice, the employment of heated air at 700.degree. C., steam at 120.degree. C., and heating medium at 120.degree. C., with findings as shown in a graph of FIG. 10, in which curves (1) and (2) represent the results as obtained by blowing hot air or steam from above the ice, while a curve (3) denotes the results when a blade through which heating medium is circulated is brought into pressure contact with the ice.
As is seen from FIG. 10, for forming line grooves of 20 mm in depth on the surface of the ice plate, more than 30 seconds are required for the method represented by curve (1), 3 to 4 seconds for the method represented by curve (2) and 6 to 7 seconds for the method represented by curve (3). Thus, as shown by the curves (2) and (3), processing speeds were almost the same as those in the conventional arrangements.